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971.
The vehicle routing problem with deliveries and pickups is a challenging extension to the vehicle routing problem that lately
attracted growing attention in the literature. This paper investigates the relationship between two versions of this problem,
called “mixed” and “simultaneous”. In particular, we wish to know whether a solution algorithm designed for the simultaneous
case can solve the mixed case. To this end, we implement a metaheuristic based on reactive tabu search. The results suggest
that this approach can yield good results. 相似文献
972.
Rónán Kennedy 《Information & Communications Technology Law》2008,17(2):95-106
The new industry of Massively Multi-Player Online Role-Playing Games (MMORPGs) brings together two sets of fictions: the interactive stories of shared computer games and the legal devices of intellectual property. In these virtual worlds, scarcity need not exist, but players tend to prefer the competition it creates. This leads to the development of property rights within the game world and players trading real money for virtual objects, ‘land’ and characters. This new phenomenon brings with it familiar legal problems such as theft, fraud and ownership disputes. Game creators also challenge the right of the players to claim ownership outside the game world. The volume and value of the items traded make real money trading an important area of current interest for intellectual property lawyers. Something is being traded, but does it fit neatly into existing conceptions of property rights and who owns it? Analysing the novel problems that result from various theoretical perspectives (utilitarianism, labour-desert theory and personality theory) leads to the conclusion that with time, we will see the development of property rights for players in online games. This connects with a growing understanding that the traditional conception of copyright law dealing with creative work generated by the solitary author is becoming less appropriate in the new creative spaces that information and communications technology brings, where individuals are both consumer and producer. In virtual worlds, new forms of intellectual property, and perhaps even new rights, are taking shape. 相似文献
973.
Predictive modelling of online dynamic user-interaction recordings and community identification from such data becomes more
and more important with the widespread use of online communication technologies. Despite of the time-dependent nature of the
problem, existing approaches of community identification are based on static or fully observed network connections. Here we
present a new, dynamic generative model for the inference of communities from a sequence of temporal events produced through
online computer- mediated interactions. The distinctive feature of our approach is that it tries to model the process in a
more realistic manner, including an account for possible random temporal delays between the intended connections. The inference
of these delays from the data then forms an integral part of our state-clustering methodology, so that the most likely communities
are found on the basis of the likely intended connections rather than just the observed ones. We derive a maximum likelihood
estimation algorithm for the identification of our model, which turns out to be computationally efficient for the analysis
of historical data and it scales linearly with the number of non-zero observed (L + 1)-grams, where L is the Markov memory length. In addition, we also derive an incremental version of the algorithm, which could be used for
real-time analysis. Results obtained on both synthetic and real-world data sets demonstrate the approach is flexible and able
to reveal novel and insightful structural aspects of online interactions. In particular, the analysis of a full day worth
synchronous Internet relay chat participation sequence, reveals the formation of an extremely clear community structure. 相似文献
974.
Štefan Černák 《Soft Computing - A Fusion of Foundations, Methodologies and Applications》2008,12(5):453-462
A convergence with a fixed regulator v in lattice ordered groups is applied to MV-algebras. For each Archimedean MV-algebra A there exists a v-Cauchy completion A
* and it is uniquely determined up to isomorphisms over A. The relation between the Dedekind completion A
∧ of A and A
* is established. There is solved a question of the existence of the greatest v-Cauchy complete ideal of A. 相似文献
975.
Staged self-assembly: nanomanufacture of arbitrary shapes with <Emphasis Type="Italic">O</Emphasis>(1) glues 总被引:1,自引:1,他引:0
Erik D. Demaine Martin L. Demaine Sándor P. Fekete Mashhood Ishaque Eynat Rafalin Robert T. Schweller Diane L. Souvaine 《Natural computing》2008,7(3):347-370
We introduce staged self-assembly of Wang tiles, where tiles can be added dynamically in sequence and where intermediate constructions can be stored for later
mixing. This model and its various constraints and performance measures are motivated by a practical nanofabrication scenario
through protein-based bioengineering. Staging allows us to break through the traditional lower bounds in tile self-assembly
by encoding the shape in the staging algorithm instead of the tiles. All of our results are based on the practical assumption
that only a constant number of glues, and thus only a constant number of tiles, can be engineered. Under this assumption,
traditional tile self-assembly cannot even manufacture an n × n square; in contrast, we show how staged assembly in theory enables manufacture of arbitrary shapes in a variety of precise
formulations of the model.
相似文献
Diane L. SouvaineEmail: |
976.
Johan Montagnat Ákos Frohner Daniel Jouvenot Christophe Pera Peter Kunszt Birger Koblitz Nuno Santos Charles Loomis Romain Texier Diane Lingrand Patrick Guio Ricardo Brito Da Rocha Antonio Sobreira de Almeida Zoltán Farkas 《Journal of Grid Computing》2008,6(1):45-59
The medical community is producing and manipulating a tremendous volume of digital data for which computerized archiving,
processing and analysis is needed. Grid infrastructures are promising for dealing with challenges arising in computerized
medicine but the manipulation of medical data on such infrastructures faces both the problem of interconnecting medical information
systems to Grid middlewares and of preserving patients’ privacy in a wide and distributed multi-user system. These constraints
are often limiting the use of Grids for manipulating sensitive medical data. This paper describes our design of a medical
data management system taking advantage of the advanced gLite data management services, developed in the context of the EGEE
project, to fulfill the stringent needs of the medical community. It ensures medical data protection through strict data access
control, anonymization and encryption. The multi-level access control provides the flexibility needed for implementing complex
medical use-cases. Data anonymization prevents the exposure of most sensitive data to unauthorized users, and data encryption
guarantees data protection even when it is stored at remote sites. Moreover, the developed prototype provides a Grid storage
resource manager (SRM) interface to standard medical DICOM servers thereby enabling transparent access to medical data without
interfering with medical practice. 相似文献
977.
Sandoval-Romero GE García-Valenzuela A Sánchez-Pérez C Hernández-Cordero J Muratikov KL 《The Review of scientific instruments》2007,78(10):104901
We propose and study a novel optoelectronic device for thermal characterization of materials. It is based on monitoring the photothermal deflection of a laser beam within a slab of a thermo-optic material in thermal contact with the sample under study. An optical angle sensor is used to measure the laser deflection providing a simple and experimental arrangement. We demonstrate its principle and a simple procedure to measure thermal effusivity of liquids. The proposed device could be implemented into a compact sensor head for remote measurements using electrical and fiber optic links. 相似文献
978.
Boulahya K Ruiz-González L Parras M González-Calbet JM Nickolsky MS Nicolopoulos S 《Ultramicroscopy》2007,107(6-7):445-452
Two complex perovskite-related structures were solved by ab initio from precession electron diffraction intensities. Structure models were firstly derived from HREM images and than have been confirmed independently using two and three-dimensional sets of precession intensities. Patterson techniques prove to be effective for ab initio structure resolution, specially in case of projections with no overlapping atoms. Quality of precession intensity data may be suitable enough to resolve unknown heavy oxide structures. 相似文献
979.
The effect of illuminance on the speed and the quality (percentage of errors) with which workers assemble electronic devices was studied in an electronics factory in The Netherlands. For the study, the horizontal illuminance was alternated per work shift between 800 and 1200 lux. The first test was done during the summer and a second test during the winter. A significant effect of illuminance has been found. With 1200 lux at the working plane, the speed of production in the summer was 2.9% higher than with 800 lux. In the winter it was 3.1% higher with the increased illuminance. There was no significant effect of the illuminance on the percentage of errors. 相似文献
980.